Clipped Samples Research Articles

188 Prediction of individual grazing beef cattle dry matter intake

Abstract Estimation of individual dry matter intake (DMI) of pastured beef cattle is critical to grassland management, genetic improvement of efficiency, and increasing the sustainability of animal agriculture. Currently, the only way to measure individual DMI of grazing cattle is through expensive, labor intensive, and spatially demanding research protocol. Very few options for assessment of individual DMI of grazing animals exist for cattle producers. We have developed a machine learning approach to predicting individual DMI of pastured beef cattle that requires only body weight (BW), water intake, and open-source climate variables. Training data were collected in Wardensville, WV at the West Virginia University Research, Outreach, and Education Center. Crossbred steers (n = 32) were phenotyped for Residual Feed Intake (RFI) in the barn. Animals were split into four groups of two low RFI and two high RFI. After a grazing acclimation period, animal groups were rotationally grazed concurrently through 0.05 ha plots for 7 d. Daily BW and water intake data were collected throughout the experiment using an RFID-equipped front-end scale and metered waterers. Beginning on d 2, animals were provided a bolus of Cr2O3 (10 g) at 0700 and 1900 h. Beginning on d 5, fecal samples were collected from each animal at 0700 and 1900 h. Samples were analyzed for Cr2O3 content and used in conjunction with forage digestibility from paired clipped samples to generate individual intakes. These data were used as ground truth data to assess model performance. We used our Repeated Measures Random Forest (RMRF) model to predict individual DMI of animals using daily BW, water intake, and climate variables. Intakes estimated by RMRF were compared with intakes estimated by NASEM equations. Our model outperformed NASEM predictions by 70%, indicating that our method achieves better results than the current most efficient approach. Though iterative model improvements will be made (collection of more training data, collection of more diverse training data, and use of first-differenced, moving average, and seasonally adjusted variables), our work demonstrates a novel, efficient method for researchers and producers to more accurately estimate DMI of individual pastured beef cattle.

Automatic Detection of Amplitude-Distorted Samples from Clipped Seismic Waveforms

AbstractSeismic waveforms are essential for seismology but are clipped when their actual amplitudes are too high to be faithfully recorded by seismometers. The clipping effects are popular for both big earthquakes and small earthquakes within a short epicentral distance. Here, we illustrate potential risks of direct usage of clipped waveforms by examining the frequency leakage and show the failure of bandpass filtering for different clipping levels; then we summarize two characteristics of clipped records: (1) The temporal gradient is unusually large around the clipped segment compared with the unclipped portions, and (2) the clipped samples cluster into one segment or several if many samples are involved. Next, we propose three criteria for distinguishing clipped samples from the perfect samples based on these two characteristics. Finally, we design a numerical algorithm for automatic detection of clipped samples using constraints on the gradient, amplitude, and gradient-varying range. Numerical experiments show the excellent performance of our algorithm on automatically detecting the clipped samples. Our algorithm seamlessly integrates all necessary constraints for both flat-top type and back-to-zero type and thus can correctly recognize these two types simultaneously; in addition, it is basically data driven and thus can work well without considering seismometer configuration and instrument type, which would be helpful for real-time detection of clipped records without interruption from human operations. As a robust and swift tool of automatic detection on amplitude-clipped samples, our algorithm could identify most typical clipped records and reduce potential risks due to using unrecognizable clipped waveforms; furthermore, it would be helpful for fast detection and possible restoration of clipped waveforms in the presence of huge volumes of data.

Plate meter calibrations for forage mass follow a continuum of sward basal density

AbstractThe ability to quantify forage mass (FM) is needed when budgeting pasture supply. Calibrated sward height is an indirect measure of FM. In a previous study, it was observed that the regression intercept and slope of forage density vs. height (FDint and FDslope, respectively) had a strong linear relation, giving rise to the hypothesis that there is a calibration continuum across pastures. This hypothesis was tested using 121 plate meter calibrations conducted across a range of plant species, defoliation managements, land resource areas, latitude, and elevation. Sward compressed height (CHt) was measured using a resting plate meter. Within calibrations, 30 to 60 paired CHt and FM samples were collected: half pre‐grazing and half post‐grazing. Within calibrations, the linear relation between CHt and forage density (FD) was calculated. Across calibrations, the linear relation between FDint and FDslope was calculated. Forage mass available for grazing (FMAG) was predicted using individual calibrations and the continuum calibration and compared with forage mass grazed (FMG) measured using pre‐ and post‐grazing clipped samples. Across calibrations, there was a strong linear relation between FDint and FDslope (R2 = 0.83). Within calibrations, predicted FMAG vs. FMG was accurate and precise. Across events, predicted FMAG using the continuum was accurate but less precise. Using the continuum to estimate FMAG provided estimates within 10% for recommended grazing heights. Factors that determine the relation between FDint and FDslope include morphology of the dominate grass, species composition, tiller size/density compensation, sward growth to optimize light interception, and tiller dynamics relative to time of year.

Multi-dimensional grid-less estimation of saturated signals

This work proposes a multi-dimensional frequency and amplitude estimator tailored for noise corrupted signals that have been clipped. Formulated as a sparse reconstruction problem, the proposed algorithm estimates the signal parameters by solving an atomic norm minimization problem. The estimator also exploits the waveform information provided by the clipped samples, incorporated in the form of linear constraints that have been augmented by slack variables as to provide robustness to noise. Numerical examples indicate that the algorithm offers preferable performance as compared to methods not exploiting the saturated samples.

Amplitude reconstruction of clipped OFDM by using DFT-based least squares

OFDM is an e ective multicarrier transmission technique with one primary disadvantage; it su ers from high Peak-to-Average Power Ratio (PAPR). Although clipping and ltering is a simple and e ective method for PAPR reduction, it makes in-band and out-of-band noise, which degrades the bit error rate performance and spectral eficiency. Publications on this subject show that clipped samples could be reconstructed at the receiver by using oversampled signal and bandwidth expansion. By building on published literature, this paper aims to achieve a low-complexity method. The proposed method has complexity order of O(L2) to solve linear system, where L indicates the number of clipped samples. Simulation results con rm that our proposed method leads to both a better biterror rate performance and a lower complexity than similar methods. These results also show that our method o ers adequate performance, especially at low clipping ratios.

Effects of stocking rate on forage nutrient composition of Nebraska Sandhills upland range when grazed in early summer.

Twelve 2-ha, Nebraska Sandhills upland range paddocks were used in a 2-yr study to determine effects of stocking rate on grazed forage nutrient value in early summer. Paddocks contain a mixture of native cool- and warm-season grasses with forbs as a minor component. Stocking rates were 0 (control), 0.57 (light), and 0.85 (heavy) animal unit months per ha, respectively. Three esophageally fistulated cows collected diet samples on May 14 (d 0), May 21 (d 7), May 28 (d 14), and June 4 (d 21) in 2013 and 2014. Ten quadrats per paddock were clipped and separated into current or previous year growth on each diet sampling date. All samples were analyzed for CP, NDF, and in vitro OM disappearance, which was adjusted to an in vivo OM basis (). For diet samples, treatment interacted ( < 0.001) with sampling date for CP, NDF, and IVOMD. However, treatment and date did not interact ( ≥ 0.32) for clipped samples. Diets collected in control paddocks had greater ( < 0.05) IVOMD and CP and lower NDF compared with light and heavy stocking rate paddocks on d 7, 14, and 21 but light stocking rate paddocks did not differ ( ≥ 0.26) from heavy stocking rate paddocks on any sampling day except d 21 NDF ( = 0.03). In general, previous year growth IVOMD, CP, and NDF were not affected ( ≥ 0.11) by treatment. Generally, current year growth IVOMD and CP were not affected ( ≥ 0.22) by treatment. Current year growth NDF did not differ ( = 0.23) among stocking rates on d 0, but control paddock had lower ( = 0.02) NDF than light and heavy on d 7, 14, and 21. In stocked paddocks, diet samples had greater ( < 0.01) IVOMD and CP and lower NDF than current and previous year growth except IVOMD on d 0 where diet and current year growth did not differ ( = 0.34). Generally, in control paddocks, current year growth and diet samples had greater ( < 0.01) IVOMD and CP than previous year growth. Control paddocks had greater ( < 0.01) forage accumulation than stocked paddocks on d 7, 14, and 21; however, light and heavy stocked paddocks did not differ ( ≥ 0.29). On d 0 it was estimated that 96% of the diet was current year growth and only 4% previous year growth, whereas on d 21, 70% of the diet was current year growth vs. 30% previous year growth. Stocking pastures decrease current year growth forage mass and therefore diet nutritive value by forcing cattle to consume diets containing previous year growth in early summer.

Measuring Legume Content in Pastures Using Digital Photographs

Quantifying botanical composition is important for evaluating management effect on legume content and legume content on pasture yield and quality. The standard for measuring botanical composition is hand separation of clipped samples. An alternative is taking point counts of botanical components on photographs of the pasture. This was tested on a rotationally stocked pasture, taking photos at 24 random sample areas, clipping areas at ground level and hand separating samples into grass, legume and forb fractions. Photos were evaluated using a grid in Microsoft PowerPoint. Point counts were calibrated to hand separated values using linear regression. Grass and legume point count components were not significantly different from hand separated values (P=0.05) but underestimated the forb fraction. Calibration regressions had R 2 values ranging from 0.45 to 0.98. Precision of this technique is dependent on the number of photos/pasture, number of points counted/photo and the number of paired samples taken for calibration. In cool-season grass-clover pastures 12 or more photos/pasture and 100 or more points/photo are a good balance between photo number and points per photo. For calibration 12 or more paired samples should be used. Photo point counts appear to be a practical method of measuring grass, legume and forb components in rotationally grazed pastures.

Acceptability and nutritional value of the Teff grass for grazing horses

Acceptability and nutritional value of the Teff grass for grazing horses

Variation in nutritive quality and mineral content of grazed and clipped forage from native range in southwest Idaho

Changes in nutrient content of grazed and clipped forages during the growing season were evaluated over a 2-yr period via samples from native range in southwestern Idaho. Mature, ruminally fistulated beef cows were used from April to September (yr 1; n = 4) and May to October (yr 2, n = 3) to collect masticated diet samples every 2 to 4 wk. Clipped samples were also collected concurrent with grazed samples. Attempts were made to clip forage similar to what the cows had been observed to be consuming; however, cattle selected (P < 0.05) a diet higher in nutritive quality than what was clipped for some nutrients. In yr 1, forage CP was greater (P = 0.05) in grazed than clipped samples in July, whereas in yr 2 grazed CP tended (P = 0.06) to be greater in August and was greater (P < 0.05) in September than clipped samples. Nutrient content of samples was adequate to meet lactating beef cow needs (NRC requirements) for CP and TDN until mid to late summer and adequate for K but deficient for P, Na, Ca, Mg, and S throughout the grazing season. Micronutrients Fe, Mn, and Mo were adequate during the grazing season, whereas Cu and Zn were deficient. Based on the variation in nutrient content by month, we report that forage quality is highly variable throughout the grazing season. Furthermore, clipped sample nutrient content is generally similar to grazed sample content and provides an adequate prediction of consumed forage quality.

Dynamic Range Extension Using Interleaved Gains

We present a methodology to sample signals in such a way so as to avoid the effects of signal clipping due to a limited dynamic range. We do so by attenuating a selective subset of the data before it gets sampled, so that if clipping is detected after the sampling process we can easily estimate the missing samples using the nonclipped samples that were attenuated. We show that under sparsity assumptions it is possible to reconstruct the clipped samples and recover a satisfactory representation of the original signal. We provide an analysis of the side effects of this process and show that on average when sampling signals with highly varying or unknown gain, we can guarantee a significantly lower potential for signal distortion and noise.

Joint multi-user interference and clipping noise cancellation in uplink MC-CDMA system

In this paper, an iterative method is proposed to jointly cancel multi-user interference and clipping noise in uplink Multi-Carrier Code Division Multiple Access (MC-CDMA) systems. Clipping is the simplest method to overcome high peak-to-average power ratio of multi-carrier signals but it makes the signals distorted. Reconstruction methods use non-distorted samples to reconstruct distorted samples in the receiver but multi-user interference causes the methods do not work properly because all the received samples are distorted due to clipping and interference and so there is no undistorted samples to be used in recovering clipped samples. On the other hand, multi-user interference cancellation methods do not work properly because clipping in the transmitter is a non-linear process and therefore this process increases the amount of multiple access interference (MAI). In this paper, we propose a joint MAI and clipping noise cancellation method. In the proposed iterative method in each iteration a MC-CDMA detection method accompany with a clipping and filtering process and then by using the received signal as reference signal, an approximation of error due to clipping and residual interference is computed. Simulation results show that the proposed method improves the performance of clipped MC-CDMA systems in uplink for synchronous/asynchronous links.

Estimation of Forage Intake by Steers Grazing Three Fescue Types and Determination of Alkaloids in Ruminal Fluid and Forage

During 2 consecutive grazing seasons, DMI of steers grazing ‘Kentucky-31’endophyte (Neotyphodium coenophialum-infected tall fescue (E+; Festuca arundinacea Shreb.), ‘Kentucky-31’endophyte-free tall fescue (E-), and ‘Quantum’tall fescue infected with endophyte AR542, a non-ergot alkaloid-producing strain (Quantum) was estimated using alkanes as markers. The appearance of ergovaline and lysergic acid amide (LSA) also was quantified in forage and ruminal fluid of steers grazing these forages. Estimates of DMI did not differ(P= 0.88) when based on fecal samples collected at 0800 h, 1700 h, or a composite of the 2 sampling times. Estimation of DMI using hand-plucked samples tended to be greater (P = 0.06) than whole-plant clipped samples. Estimated DMI was greater (P < 0.05) on E- pastures than E+ or Quantum across both years. Both LSA and ergovaline were present in E+ forage throughout the grazing season but were not detectable in E- and Quantum. Similarly, LSA appeared in ruminal fluid of steers grazing E+, but not in steers grazing E- and Quantum. Ergovaline was not detectable in ruminal fluid of steers grazing any of the 3 fescue types. These data suggest time of fecal sampling does not affect DMI estimations, but method of forage sampling does. Lower DMI may affect performance of steers grazing E+ and Quantum. Additionally, the appearance of LSA in ruminal fluid of steers grazing E+ suggests that this ergot alkaloid may contribute to fescue toxicosis.

Alternative Methods of Estimating Forage Height and Sward Capacitance in Pastures Can Be Cross Calibrated

Alternative Methods of Estimating Forage Height and Sward Capacitance in Pastures Can Be Cross Calibrated

Estimation of undegradable intake protein in forages using neutral detergent insoluble nitrogen at a single in situ incubation time point1

Two experiments were conducted to evaluate the use of neutral detergent insoluble nitrogen (NDIN) at a single in situ incubation time point to estimate the undegradable intake protein (UIP) in forages as well as to compare rates of NDIN degradation. Forage samples in Exp. 1 comprised diet samples collected from range and meadow pastures monthly from May through September. In Exp. 2, clipped samples of alfalfa, birdsfoot trefoil, kura clover, and smooth bromegrass, and diet samples of the mixed legume-grass and smooth bromegrass were evaluated. Forage samples were incubated in situ for their mean retention time (MRT) estimated from IVDMD plus a 10-h passage lag to yield the total MRT (TMRT). Samples were also incubated for 0 h, 10 h, 75% TMRT, and 96 h. Undegradable intake protein was measured at 75% TMRT and TMRT, and calculated using fractional rates of degradation and passage with a 10-h passage lag. Rates of ruminal NDIN degradation were calculated using the slope of the regression of the natural logarithm of the potentially degradable NDIN remaining (96-h undegradable fraction subtracted) against time. The estimated UIP values obtained using 75% TMRT were highly correlated with those obtained using fractional rates of degradation and passage plus accounting for a 10-h passage lag in Exp. 1 (R2 = 0.95) and Exp. 2 (R2 = 0.98). Rates of NDIN degradation of range and meadow samples in Exp. 1 were slower (P < 0.05) from 0 to 10 h in May and June compared with rates from 10 h to 75% TMRT, but rates of degradation were not different (P = 0.34 to 0.71) for the rest of the collection periods. Rates of degradation were not different from 0 to 10 h and 10 h to 75% TMRT in Exp. 2 for diet (P = 0.82) or clipped samples (P = 0.86). The UIP of the forages in these experiments was accurately estimated using NDIN at a single in situ incubation time point equivalent to 75% of the TMRT, and rates of protein degradation can be obtained at this time point when 0- and 96-h incubations are included.

Beef hide antimicrobial interventions as a means of reducing bacterial contamination

This project was designed to evaluate interventions capable of reducing bacterial counts on the hide prior to opening. In Trial I, fresh beef hides ( n = 12) were cut into sections and assigned to serve as either clipped (hair trimmed) or non-clipped sections. Sections were inoculated with a bovine fecal slurry and sampled following a water wash. Treatments (distilled water, isopropyl alcohol, 3% hydrogen peroxide, 2% l-lactic acid, 10% povidone-iodine, and 1% cetylpyridinium chloride (CPC)) were then applied to each section and the sections were sampled for enumeration of aerobic plate counts (APCs), coliforms, and Escherichia coli. Within clipped samples, 1% CPC and 3% hydrogen peroxide caused the greatest reductions in APCs (4.6 and 4.4 log 10CFU/100-cm 2, respectively), and 1% CPC, 2% l-lactic acid, and 3% hydrogen peroxide caused the greatest reductions in coliform counts (4.5, 4.1, and 3.9 log 10CFU/100-cm 2, respectively). In Trial II, beef carcasses with hides on were sampled initially and clipped, and then 2% l-lactic acid, 3% hydrogen peroxide, or 1% CPC were applied before sampling. For APCs, 1% CPC produced the greatest reduction on the hide surface (3.8 log 10CFU/100-cm 2). Selective application of these antimicrobials to clipped hide opening sites reduced bacterial counts on hide surfaces, and therefore could reduce final carcass counts in these areas by decreasing the bacterial load before opening.

Characterization of season and sampling method effects on measurement of forage quality in fescue-based pastures.

Information on seasonal changes and effects of sampling methods on the measurement of forage quality is limited for fescue-based pastures. Eight continuously grazed, 0.76-ha, fescue-based pastures were used to compare forage type, method of collection, and seasonal effects on forage quality in a repeated-measures, split-plot design. Four pastures were interseeded with red clover in March 2000. Masticate (M; from four ruminally cannulated steers) and hand--clipped (C) samples were collected every 28 d from April to October 2000. Interseeding red clover did not affect (P > 0.10) OM, CP, NDF, and ADF concentrations or CP degradability. Sampling method and season interacted (P < 0.03) for OM, CP, NDF, and ADF concentrations. Concentrations of OM averaged 5 percentage units more (P < 0.01) in C than in M in all months and were more variable with M than with C. Samples clipped between April and September averaged 5.5 percentage units greater NDF (P < 0.01), 3.0 percentage units greater ADF (P < 0.01), and 4.5 percentage units less CP (P < 0.01) than masticate samples obtained during the same time period. Fiber and CP concentrations did not differ (P > 0.10) between C and M samples obtained in October. Differences in CP degradability estimates (using Streptomyces griseus protease) between the two sample types were greater in late-season samples than in samples obtained from April to June. When S. griseus protein degradability estimates were compared with in situ estimates for masticate samples, no differences (P > 0.10) were detected early in the season (April to June). However, the S. griseus procedure overestimated in situ values (P < 0.01) by an average of 3 percentage units in samples obtained between July and October. Differences in composition of C and M samples were substantial until late season, when opportunities for selective grazing were minimal. Small differences between S. griseus and in situ estimates of CP degradability indicate that the S. griseus procedure can yield useful CP degradability estimates for fescue-based pasture samples. Although it might be possible to apply correction values to clipped samples to estimate CP and fiber concentrations of diets selected by grazing cattle, inconsistent relationships preclude this approach for estimates of CP degradability.

Clipping noise cancellation in OFDM systems using oversampled signal reconstruction

Clipping the OFDM signals in the digital part of the transmitter is one of the simplest methods to reduce the peak factor. However, it suffers from additional clipping distortion, peak regrowth after digital to analog conversion, and out-of-band radiation in the case of oversampled sequence clipping. We use oversampled sequence clipping to combat the effect of peak regrowth and propose a method to reconstruct the clipped samples and mitigate the clipping distortion in the presence of channel noise at the expense of bandwidth expansion. We show through extensive simulations that by slightly increasing the bandwidth of the system, we can significantly improve the performance while limiting the maximum amplitude of the analog signal.

Nutrient selection by cattle from grass and grass/legume pastures

Esophageal fistula and hand-clipped samples were collected from a 32-yr-old crested wheatgrass (Agropyron cristatum L.) pasture and an alfalfa (Medicago sativa L.)/meadow bromegrass (Bromus biebersteinii Roem &amp; Schult.)/Russian wildrye (Psathyrostachys juncea [Fisch.] Nevski) pasture to compare estimates of nutritional quality. Samples were analyzed for crude protein (CP), in vitro digestible organic matter (IVDOM) and selected minerals. Fistula samples had greater (P &lt; 0.05) CP and IVDOM contents than clipped samples at all times except that CP did not differ (P &gt; 0.05) on two occasions and IVDOM did not differ (P &gt; 0.05) on one occasion. Differences in mineral content between clipped and esophageal samples were less consistent, but when they occurred the mineral contents of esophageal samples usually exceeded (P &lt; 0.05) those of clipped samples. We conclude that clipped pasture samples mostly provide biased estimates of the nutritional quality of herbage consumed by cattle grazing grass and grass/legume pastures and should be reported with caution. Key words: Pasture, selection, cattle, protein, digestibility, minerals

Favorable scanning electron microscopic findings of stapled saphenous vein–carotid artery anastomoses

Background. In the progress toward “off-pump” endoscopic coronary artery surgical procedures, new techniques for coronary artery anastomoses are being developed. One such approach is the use of nonpenetrating titanium clips. We evaluated the quality of anastomoses achieved using this technique in a porcine model of saphenous vein–carotid artery grafting using scanning electron microscopy. Methods. Bilateral saphenous vein–carotid artery interposition grafts were implanted in 10 “white race” pigs, using the nonpenetrating clips in one side of the neck and conventional hand suturing on the opposite side. One week after operation, the grafts were harvested. Results. All grafts were patent 7 days after operation, and 40 anastomoses underwent scanning electron microscopic study. In all samples, the luminal surfaces of both the carotid artery and vein graft were covered by a continuous layer of endothelial cells up to the anastomosis. Anastomotic sites in all clipped samples and most of the sutured anastomoses were completely endothelialized, and anastomotic clefts were indistinguishable. However, in 25% of sutured specimens, the suture material remained clearly visible inside the lumen of the vessel, and the subendothelial matrix remained exposed, with extensive fibrin, red blood cells, and platelet deposition on its surface. Conclusions. Because the endothelial coverage consistently appeared to be complete and the subendothelial matrix was not exposed, it is likely that the risk of early anastomotic thrombosis is reduced by using the nonpenetrating titanium clips.

Pasture Development during Brush Clearing with Sheep and Goats

Knowing that sheep or goats can be used to control brush we quantified pasture changes during and after brush control. Over an 8-year period we measured the effects of control (no soil amendment), medium soil amendment (4,500 kg lime and 40 kg P ha-1), and high soil amendment (9,000 kg lime and 117 kg P ha-1) on soil fertility, pasture botanical composition and production of brushy pasture grazed by sheep or goats. Botanical composition was estimated from clipped samples. Soil pH was 4.8 in the control, 6.5 in the medium and 7.0 in the high amendment plots. Medium and high amendment increased legume dry matter in the pasture from 2 in the check to 8%. More animal grazing days were obtained on paddocks treated with lime and P. Grazing with sheep or goats and lime and application of P resulted, after 4 years, in pastures with a grass, legume, and other broadleaf plant composition similar to that of brush-free, natural pasture.